Abstract: Objective To explore the effects of smalf interfering RNA(siRNA) specific to Bcl-2 gene on radiosensitivity of oesophageal cancer cells.Methods The eukaryotic expression vector of Bcl-2 gene siRNA was constructed and introduced into oesophageal cancer cells EC 109 by lipofectamine. Bcl-2 protein expression in EC 109 cells was detected by Western blot. Flow cytometry was employed to evaluate apoptosis of EC109. Clone forming assay and nude mice xenograft assay were used to determine the inhibitory effects of X radiation combined with Bcl-2 gene specific siRNA.Results Western blot analysis demonstrated that eukaryotic expression vector of Bcl-2 gene siRNA successfully suppressed Bcl-2 protein expression in EC 109 cells. Bcl-2 gene siRNA could induce apoptosis of EC 109 cells, enhance the inhibitory effects of X radiation on clone forming ability of EC 109 cells and xenograft growth in nude mice.Conclusion The eukaryotic expression vector of Bcl-2 gene siRNA could enhance the radiosensitivity of oesophageal cancer cells and can be used as a powerful adjunct to conventional radiotherapy.